What is the sediment deposited by surface water?

The sliding filament theory is the illustration that how the contraction of muscles takes place in order to generate force. At the start of the process, the motor neuron instigates an action potential or impulse to pass down a nerve cell to the neuromuscular junction. This activates the sarcoplasmic reticulum, which discharges calcium into the cells of the muscles.  

When calcium comes within the muscle cells, it combines with troponin, thus, permitting the binding of actin with myosin. The actin and myosin bind with each other and form cross-bridges, which further contracts by utilizing ATP as the source of energy.  

ATP is manufactured again, thus, permitting actin and myosin to sustain their strong binding condition. Relaxation takes place when stimulation of the nerve ceases. Calcium is then moved back within the sarcoplasmic reticulum dissociating the association between the actin and myosin.  

The actin and myosin go back to their unbound condition making the muscle to relax.